The authors analyzed the problem of building information modeling (BIM) applied in structural engineering field, and put forward the theory of BIMmethodology which was composed of the basic principle of BIM and structure BIM model. The basic principle of BIM was modeled and analyzed by mathematicalmodeling. The conclusion of the modeling solved the problem of using and researching BIM by the structural engineers. Meanwhile, the model of the theory also laid the groundwork for the future quantitative BIM study. In the end, the important practical significance of the theory was discussed and the branch of structure BIM model was raised. The conclusion lays the foundation for further discussion of organization structure of BIM model method.